U.S. patent application number 15/827215 was filed with the patent office on 2019-05-30 for systems and methods for applying vacuum pressure to composite parts.
This patent application is currently assigned to The Boeing Company. The applicant listed for this patent is The Boeing Company. Invention is credited to Kenneth M. Dull, Michael K. Louie, Gagandeep Saini.
Application Number | 20190160714 15/827215 |
Document ID | / |
Family ID | 63524213 |
Filed Date | 2019-05-30 |
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United States Patent
Application |
20190160714 |
Kind Code |
A1 |
Louie; Michael K. ; et
al. |
May 30, 2019 |
Systems and Methods for Applying Vacuum Pressure to Composite
Parts
Abstract
A vacuum probe comprises a sharpened body that is displaceable
downward and toward a vacuum bag during vacuum hose quick
connection. The sharpened body and a valve element inside the
vacuum probe move in tandem until the sharpened body projects
outside the vacuum probe. A vacuum pressure applied via the vacuum
hose pulls the vacuum bag upwards and towards the projecting
sharpened body, which then punctures the vacuum bag, thereby
enabling air under the vacuum bag to be evacuated via the vacuum
probe as vacuum pressure continues to be applied.
Inventors: |
Louie; Michael K.; (Renton,
WA) ; Dull; Kenneth M.; (Puyallup, WA) ;
Saini; Gagandeep; (Snohomish, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Boeing Company |
Chicago |
IL |
US |
|
|
Assignee: |
The Boeing Company
Chicago
IL
|
Family ID: |
63524213 |
Appl. No.: |
15/827215 |
Filed: |
November 30, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 37/1009 20130101;
B29C 2043/3644 20130101; B29C 70/443 20130101; B29C 43/3642
20130101; F16L 37/0982 20130101; F16K 15/06 20130101; B29C 70/44
20130101; B29C 43/3607 20130101; F16K 15/063 20130101; B32B 37/1018
20130101 |
International
Class: |
B29C 43/36 20060101
B29C043/36; B29C 70/44 20060101 B29C070/44; F16K 15/06 20060101
F16K015/06; F16L 37/098 20060101 F16L037/098 |
Claims
1. A method for applying vacuum pressure to a composite part,
comprising: (a) placing a composite part on a tool; (b) placing a
sealant tape on the tool along a perimeter that surrounds the
composite part; (c) laying a vacuum bag over the composite part and
in contact with the sealant tape; (d) placing a vacuum probe
overlying a portion of the vacuum bag with sealing material
disposed between the vacuum probe and the vacuum bag, the vacuum
probe comprising a sharpened body; (e) coupling a vacuum hose to an
end of the vacuum probe in a manner that causes a valve element to
separate from a valve seat inside a vacuum channel of the vacuum
probe; and (f) applying a vacuum pressure inside the vacuum channel
by way of the vacuum hose, as a result of which a portion of the
vacuum bag surrounded by the sealing material is pulled toward and
punctured by the sharpened body.
2. The method as recited in claim 1, wherein coupling the vacuum
hose to the end of the vacuum probe also causes the sharpened body
to move in tandem with the valve element in a direction away from
the valve seat until the sharpened body protrudes outside the
vacuum channel and into a space overlying the vacuum bag.
3. The method as recited in claim 2, wherein the sharpened body is
connected to a rod that is connected to the valve element.
4. The method as recited in claim 2, wherein the sharpened body is
connected to a rod that butts against and is not connected to the
valve element.
5. The method as recited in claim 1, wherein step (e) comprises
inserting a male quick connect/disconnect coupling element of the
vacuum probe into a female quick connect/disconnect coupling
element of the vacuum hose.
6. The method as recited in claim 1, wherein the vacuum probe
comprises an externally threaded portion that projects into a space
bounded by the sealing material.
7. The method as recited in claim 6, further comprising threadably
coupling an internally threaded end cap to the externally threaded
portion of the vacuum probe, wherein the sharpened body projects
through an opening in and is axially displaceable relative to the
internally threaded end cap.
8. The method as recited in claim 6, further comprising inserting a
portion of a plug made of porous material in a portion of the
vacuum channel disposed in the externally threaded portion of the
vacuum probe, wherein the sharpened body projects from the
plug.
9. A vacuum probe comprising: a vacuum channel having an axis and
first and second openings at opposite ends thereof; and a sharpened
body that points away from the first opening of the vacuum channel
and projects outside of the vacuum channel in a vicinity of the
second opening of the vacuum channel.
10. The vacuum probe as recited in claim 9, further comprising: a
valve seat surrounding the first opening of the vacuum channel; a
valve element that is axially displaceable in the vacuum channel
between first and second axial positions, the valve element being
in contact with the valve seat while in the first axial position
and being separated from the valve seat while in the second axial
position; and a rod disposed in the vacuum channel, the rod having
a first end to which the sharpened body is fixedly coupled and a
second end that is either connected to or in abutment with the
valve element, wherein the sharpened body is axially displaceable
in tandem with the valve element as the valve element moves toward
the second axial position and projects outside the vacuum channel
when the valve element is in the second axial position.
11. The vacuum probe as recited in claim 10, wherein the second end
of the rod is connected to the valve element, further comprising an
air-permeable sharpened body support element to which the first end
of the rod and the sharpened body are affixed.
12. The vacuum probe as recited in claim 11, wherein the
air-permeable sharpened body support element is a disk having at
least one through-hole.
13. The vacuum probe as recited in claim 10, further comprising: an
externally threaded portion having a portion of the vacuum channel
disposed therein; and an air-permeable sharpened body support
element seated inside the portion of the vacuum channel that is
disposed in the externally threaded portion and to which the
sharpened body is affixed.
14. The vacuum probe as recited in claim 10, wherein the second end
of the rod is in abutment with the valve element, further
comprising a spring that urges the rod toward the valve
element.
15. The vacuum probe as recited in claim 10, further comprising an
externally threaded portion projecting downward from a bottom of
the vacuum probe, an internally threaded end cap threadably coupled
to the externally threaded portion, and a chamber affixed to the
internally threaded end cap, wherein the internally threaded end
cap comprises an opening through which the sharpened body passes,
while the chamber comprises an opening through which the rod
passes.
16. The vacuum probe as recited in claim 15, wherein the internally
threaded end cap comprises through-holes which allow air to flow
into the chamber, while the chamber comprises through-holes which
allow air to flow out of the chamber and into the vacuum
channel.
17. A system for applying vacuum pressure to a composite part,
comprising: a tool that supports a composite part; a vacuum bag
overlying the composite part supported by the tool; a flexible
sealant tape that seals the vacuum bag to the tool along a
perimeter that surrounds the composite part; sealing material on an
exterior surface of the vacuum bag within the perimeter and
separated from the composite part; a vacuum probe on top of the
sealing material, wherein the vacuum probe comprises a vacuum
channel having an axis and first and second openings at opposite
ends thereof, a valve seat surrounding the first opening, a valve
element that is axially displaceable in the vacuum channel between
a first axial position in contact with the valve seat and a second
axial position separated from the valve seat, and a sharpened body
that points away from the first opening of the vacuum channel and
projects outside of the vacuum channel in a vicinity of the second
opening of the vacuum channel; and a vacuum hose coupled to an end
of the vacuum probe in a manner that causes the valve element to
axially displace from the first axial position to the second axial
position during coupling.
18. The system as recited in claim 17, further comprising a rod
having a first end to which the sharpened body is fixedly coupled
and a second end that is either connected to or in abutment with
the valve element, wherein the sharpened body is axially
displaceable in tandem with the valve element as the valve element
moves toward the second axial position and projects into a space
surrounded by the sealing material when the valve element is in the
second axial position.
19. The system as recited in claim 18, wherein the second end of
the rod is connected to the valve element, further comprising an
air-permeable sharpened body support element to which the first end
of the rod and the sharpened body are affixed.
20. The system as recited in claim 17, further comprising: an
externally threaded portion having a portion of the vacuum channel
disposed therein; and an air-permeable sharpened body support
element seated inside the portion of the vacuum channel that is
disposed in the externally threaded portion and to which the
sharpened body is affixed.
21. The system as recited in claim 20, wherein the air-permeable
sharpened body support element is a plug made of porous
material.
22. The system as recited in claim 17, the vacuum probe further
comprises: an externally threaded portion projecting into the space
surrounded by the donut-shaped sealant tape; an internally threaded
end cap threadably coupled to the externally threaded portion of
the vacuum probe; and a chamber affixed to the internally threaded
end cap, wherein the internally threaded end cap comprises an
opening (66) through which the sharpened body passes, while the
chamber comprises an opening through which the rod passes.
23. The system as recited in claim 22, wherein the internally
threaded end cap comprises through-holes which allow air to flow
into the chamber, while the chamber comprises through-holes which
allow air to flow out of the chamber and into the vacuum channel.
Description
BACKGROUND
[0001] This disclosure relates to manufacturing of parts made of
composite material. In particular, this disclosure relates to
applying vacuum pressure to composite parts made of
fiber-reinforced plastic material.
[0002] The use of fiber reinforced/resin matrix composite materials
in the manufacture of articles and components is becoming
increasingly widespread in a number of industries, including the
aircraft industry. Such composite materials include, for example,
carbon fiber-reinforced/epoxy resin matrix materials and glass
fiber-reinforced/polyimide resin matrix materials. In a common
manufacturing procedure for producing articles and components from
composite materials, a plurality of layers of the material,
typically called a "lay-up", are held on a tool, and the tool with
the lay-up thereon is placed in an autoclave, which applies heat
and pressure, to cure the resin matrix. During the curing process,
the lay-up is covered by an impermeable, flexible film, often
referred to as the "vacuum bag" and sealed to the tool with a
vacuum bag sealant. In this way, the autoclave pressure is
transmitted uniformly over the surface of the lay-up. The uniform
pressure produces a high-quality finished article or component and
is particularly important in the manufacture of aircraft parts
which must meet stringent tolerance limitations and/or structural
strength requirements. In preparation for the curing procedure, a
vacuum probe (a.k.a. vacuum port) is placed in fluid communication
with a sealed space underneath the vacuum bag and connected to a
vacuum line. A vacuum is drawn through the line and the probe to
evacuate air between the vacuum bag and the lay-up. This presses
the vacuum bag against the lay-up so that the desired uniform
pressure will be achieved.
[0003] When vacuum is used to extract air from between the tool and
vacuum bag using a matrix of breather material, a pressure
differential is created. This differential creates a pressure from
the outside the vacuum bag pressing on the lay-up. When placed in
an autoclave with higher pressure and heat, these higher pressures
are transferred to the lay-up. Currently, in a typical composite
part/vacuum bag setup, air and volatiles are removed from the
lay-up side of the vacuum bag through one or more vacuum probes.
These probes require bases to be installed inside the composite
vacuum bag. The vacuum probes and vacuum line system are used to
maintain the pressure differential.
[0004] Heated volatiles and moisture can overload the vacuum
system. Also leaks in the system can affect the lay-up quality. The
use of additional vacuum probes ensures sufficient vacuum is
applied to composite parts and helps to minimize these effects.
Frequently, if a technician wants to apply additional vacuum, the
technician pulls up a portion of the vacuum bag sealant to insert
an additional vacuum probe base. This process disturbs the existing
vacuum condition in the bag. For complex parts, adding probes may
not be possible or may require the technician to rework the vacuum
bag in many areas due to the loss of vacuum. Adding new probes may
also deform the bag, remove existing bag pleats, or introduce bag
wrinkles. There is a need for improved systems and methods for
applying sufficient vacuum to composite parts, for example, through
the addition of vacuum probes in a vacuum bagged part.
SUMMARY
[0005] The subject matter disclosed in detail below is directed to
systems and methods for applying vacuum pressure to composite
parts. In accordance with some embodiments, a vacuum probe can be
produced specifically for adding on the exterior surface of a
vacuum bag. The vacuum probe incorporates a device that punctures
the vacuum bag during the process of connecting the vacuum probe to
a vacuum source by means of a vacuum hose, e.g., during a quick
connect/disconnect coupling of the male end of the vacuum probe and
the female end of the vacuum hose by inserting the former into the
latter. In accordance with other embodiments, some existing vacuum
probes having an externally threaded portion for threaded coupling
with a base that can be modified or supplemented to produce a
similar effect without using the base.
[0006] In accordance with the aforementioned embodiments, when a
vacuum probe is added and sealed to the exterior surface of the
vacuum bag using vacuum bag sealant tape in the shape of a donut,
the vacuum probe itself becomes a sealed-off environment. [As used
herein, the term "donut-shaped" means having a shape of a
continuous mass of material that surrounds and bounds an open
volume.] The vacuum probe comprises a sharpened body that is
recessed slightly for safety reasons, but is displaced downward and
toward the vacuum bag during vacuum hose quick connection. When
connected, the sharpened body and a valve element move in tandem in
the vacuum channel until the sharpened body projects outside the
vacuum probe. A vacuum pressure applied via the vacuum hose pulls
the vacuum bag upwards and towards the sharpened body, which
punctures the vacuum bag, thereby enabling air under the vacuum bag
to be evacuated via the added vacuum probe as vacuum pressure
continues to be applied.
[0007] Although various embodiments of systems and methods for
applying vacuum pressure to composite parts are described in some
detail later herein, one or more of those embodiments may be
characterized by one or more of the following aspects.
[0008] One aspect of the subject matter disclosed in detail
hereinafter is a method for applying vacuum pressure to a composite
part, comprising: (a) placing a composite part on a tool; (b)
placing a flexible sealant tape on the tool along a perimeter that
surrounds the composite part; (c) laying a vacuum bag over the
composite part and in contact with the sealant tape; (d) placing a
vacuum probe overlying a portion of the vacuum bag with sealing
material disposed between the vacuum probe and the vacuum bag, the
vacuum probe comprising a sharpened body; (e) coupling a vacuum
hose to an end of the vacuum probe in a manner that causes a valve
element to separate from a valve seat inside a vacuum channel of
the vacuum probe; and (f) applying a vacuum pressure inside the
vacuum channel by way of the vacuum hose, as a result of which a
portion of the vacuum bag surrounded by the sealing material is
pulled toward and punctured by the sharpened body. In accordance
with some embodiments, coupling the vacuum hose to the end of the
vacuum probe also causes the sharpened body to move in tandem with
the valve element in a direction away from the valve seat until the
sharpened body protrudes outside the vacuum channel and into a
space overlying the vacuum bag. In one proposed implementation,
step (e) comprises inserting a male quick connect/disconnect
coupling element of the vacuum probe into a female quick
connect/disconnect coupling element of the vacuum hose.
[0009] In accordance with some embodiments of the method described
in the preceding paragraph, the vacuum probe comprises an
externally threaded portion that projects into a space bounded by
the sealing material. In accordance with one embodiment, the method
further comprises threadably coupling an internally threaded end
cap to the externally threaded portion of the vacuum probe, wherein
the sharpened body projects through an opening in and is axially
displaceable relative to the internally threaded end cap. In
accordance with another embodiment, the method further comprises
inserting a portion of a plug made of porous material in a portion
of the vacuum channel disposed in the externally threaded portion
of the vacuum probe, wherein the sharpened body projects from the
plug.
[0010] Another aspect of the subject matter disclosed in detail
hereinafter is a vacuum probe comprising: a vacuum channel having
an axis and first and second openings at opposite ends thereof; and
a sharpened body that points away from the first opening of the
vacuum channel and projects outside of the vacuum channel in a
vicinity of the second opening of the vacuum channel.
[0011] In accordance with some embodiments, the vacuum probe
further comprises: a valve seat surrounding the first opening of
the vacuum channel; a valve element that is axially displaceable in
the vacuum channel between first and second axial positions, the
valve element being in contact with the valve seat while in the
first axial position and being separated from the valve seat while
in the second axial position; and a rod disposed in the vacuum
channel, the rod having a first end to which the sharpened body is
fixedly coupled and a second end that is either connected to or in
abutment with the valve element. In these embodiments, the
sharpened body is axially displaceable in tandem with the valve
element as the valve element moves toward the second axial position
and projects outside the vacuum channel when the valve element is
in the second axial position.
[0012] In cases where the second end of the rod is connected to the
valve element, the vacuum probe further comprises an air-permeable
sharpened body support element to which the first end of the rod
and the sharpened body are affixed. In one proposed implementation,
the air-permeable sharpened body support element is a disk having
at least one through-hole. In cases where the second end of the rod
is in abutment with the valve element, the vacuum probe further
comprises a spring that urges the rod toward the valve element.
[0013] In accordance with some embodiments, the vacuum probe
further comprises an externally threaded portion projecting
downward from a bottom of the vacuum probe. In one proposed
implementation, the vacuum probe further comprises an internally
threaded end cap threadably coupled to the externally threaded
portion and a chamber affixed to the internally threaded end cap,
wherein the internally threaded end cap comprises an opening
through which the sharpened body passes, while the chamber
comprises an opening through which the rod passes. To facilitate
the flow of air through the vacuum probe during evacuation, the
internally threaded end cap may comprise through-holes which allow
air to flow into the chamber, while the chamber may comprise
through-holes which allow air to flow out of the chamber and into
the vacuum channel. In another proposed implementation, the vacuum
probe further comprises an air-permeable sharpened body support
element in the form of a porous plug seated inside the portion of
the vacuum channel that is disposed in the externally threaded
portion and to which the sharpened body is affixed.
[0014] A further aspect of the subject matter disclosed in detail
hereinafter is a system for applying vacuum pressure to a composite
part, comprising: a tool that supports a composite part; a vacuum
bag overlying the composite part; a flexible sealant tape that
seals the vacuum bag to the tool along a perimeter that surrounds
the composite part; sealing material on an exterior surface of the
vacuum bag within the perimeter and separated from the composite
part; a vacuum probe on top of the sealing material; and a vacuum
hose coupled to an end of the vacuum probe in a manner that causes
a valve element of the vacuum probe to axially displace from the
first axial position to the second axial position during coupling.
The vacuum probe comprises a vacuum channel having an axis and
first and second openings at opposite ends thereof, a valve seat
surrounding the first opening, a valve element that is axially
displaceable in the vacuum channel between a first axial position
in contact with the valve seat and a second axial position
separated from the valve seat, and a sharpened body that points
away from the first opening of the vacuum channel and projects
outside of the vacuum channel in a vicinity of the second opening
of the vacuum channel.
[0015] In accordance with some embodiments, the system further
comprises a rod having a first end to which the sharpened body is
fixedly coupled and a second end that is either connected to or in
abutment with the valve element, wherein the sharpened body is
axially displaceable in tandem with the valve element as the valve
element moves toward the second axial position and projects into a
space surrounded by the sealing material when the valve element is
in the second axial position. In cases where the second end of the
rod is connected to the valve element, the vacuum probe further
comprises an air-permeable sharpened body support element to which
the first end of the rod and the sharpened body are affixed. In
cases where the second end of the rod abuts the valve element, the
vacuum probe further comprises: an externally threaded portion
projecting into the space surrounded by the sealing material; an
internally threaded end cap threadably coupled to the externally
threaded portion of the vacuum probe; and a chamber affixed to the
internally threaded end cap, wherein the internally threaded end
cap comprises an opening through which the sharpened body passes,
while the chamber comprises an opening through which the rod
passes.
[0016] Other aspects of systems and methods for applying vacuum
pressure to composite parts are disclosed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The features, functions and advantages discussed in the
preceding section can be achieved independently in various
embodiments or may be combined in yet other embodiments. Various
embodiments will be hereinafter described with reference to
drawings for the purpose of illustrating the above-described and
other aspects. None of the diagrams briefly described in this
section are drawn to scale.
[0018] FIG. 1 is a diagram representing an exploded side view of a
vacuum bag assembly for evacuating a sealed space underneath a
vacuum bag and surrounding a composite part laid on a tool.
[0019] FIG. 2 is a diagram representing a partially sectional view
of a vacuum probe in accordance with one embodiment.
[0020] FIG. 3 is a diagram representing an orthographic view of a
portion of a device which is incorporated in the vacuum probe
depicted in FIG. 2 and which is designed to puncture a vacuum bag
in response to vacuum hose hookup.
[0021] FIG. 4 is a diagram representing a partially sectional view
of a vacuum probe in accordance with another embodiment.
[0022] FIG. 5 is a diagram representing a partially sectional view
of a vacuum probe in accordance with a further embodiment.
[0023] FIG. 5A is a diagram representing a magnified view of a
portion of the vacuum probe depicted in FIG. 5.
[0024] Reference will hereinafter be made to the drawings in which
similar elements in different drawings bear the same reference
numerals.
DETAILED DESCRIPTION
[0025] For the purpose of illustration, systems and methods for
applying vacuum pressure to composite parts will now be described
in some detail. However, not all features of an actual
implementation are described in this specification. A person
skilled in the art will appreciate that in the development of any
such embodiment, numerous implementation-specific decisions must be
made to achieve the developer's specific goals, such as compliance
with system-related and business-related constraints, which will
vary from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time-consuming, but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure.
[0026] FIG. 1 is a diagram representing an exploded side view of a
typical vacuum bag assembly 10 for evacuating a sealed space
underneath a vacuum bag 18 and surrounding a composite part 4 laid
on a tool 2. A release film 14 overlies the composite part 4. A
breather cloth 16 overlies the release film. (As used herein, the
term "breather" means a porous material.) In turn, a vacuum bag 18
(made, e.g., of a sheet of nylon film) covers the breather cloth
16. The vacuum bag 18 is typically sealed to the surface of tool 2
by sealing tape 20 which surrounds the breather cloth 16 and the
composite part 4. In an unevacuated state, the vacuum bag 18 fits
loosely over the breather cloth 16, leaving open space
therebetween.
[0027] Still referring to FIG. 1, the outer peripheries of the
release film 14 and breather cloth 16 are sandwiched between an
edge breather 22 (placed on the tool 2) and a vacuum probe base 6
having an internal threads for threadably engaging an externally
threaded portion 12 of a vacuum probe 8. Typically the release film
14 does not end at the same place as the breather 16 and the edge
breather 22. It will usually end halfway over the edge breather 22
or prior to it. This is because the breather 16 should make contact
with the edge breather 22 to facilitate air flow. If the release
film 14 is non-porous, the release film 14 can cut off flow.
[0028] The coupling of the vacuum probe 8 to the vacuum probe base
6 is accomplished by forming an opening (not shown) in the vacuum
bag 18, through which the externally threaded portion 12 of vacuum
probe 8 is passed and then screwed into an internally threaded hole
in the vacuum probe base 6. When vacuum probe 8 and vacuum probe
base 6 are assembled (not shown in FIG. 1), the opening in the
vacuum bag 18 is sealed by a sealant gasket 52, which is made of a
compressible material that is squeezed between opposing surfaces of
vacuum probe 8 and vacuum probe base 6 to seal around the opening
in the vacuum bag 18.
[0029] The vacuum probe 8 is connected to a vacuum source 30 by
means of a vacuum hose 28. A common type of coupling used to
connect a vacuum hose 28 to a vacuum probe 8 is a valved quick
connect/disconnect coupling. The structure and operation of various
types of valved quick connect/disconnect couplings are well known,
including many such couplings which are commercially available from
Swagelok Company, Solon, Ohio. More specifically, detailed
descriptions of various valved quick connect/disconnect couplings
can be found in U.S. Pat. Nos. 4,378,028, 4,982,761 and 6,669,168,
which patents are assigned to Swagelok Company. In the example,
depicted in FIG. 1, the vacuum hose 28 is coupled to the vacuum
probe 8 by inserting a male quick connect/disconnect coupling
element 24 disposed at one end of the vacuum probe 8 into a female
quick connect/disconnect coupling element 26 disposed at one end of
the vacuum hose 28. The female quick connect/disconnect coupling
element 26 in turn incorporates a valve core (not shown in the
drawings) that comes into contact with and then pushes inward a
valve element (not shown in FIG. 1, but see valve element 38 in
FIG. 2) that is incorporated in the vacuum probe 8.
[0030] FIG. 2 is a diagram representing a partially sectional view
of a vacuum probe 32a comprising a male quick connect/disconnect
coupling element 24 and a flat probe bottom part 36 in accordance
with one embodiment. This vacuum probe 32a has a valve seat 50 that
surrounds an opening 58 and a valve element 38 that bears against
the valve seat 50 in the absence of a downward force sufficient to
overcome the resistance of a spring 60 that urges the valve element
38 toward the valve seat 50. The spring 60 is seated on a spring
seat 62, which may take the form of an inwardly directed annular
flange inside the vacuum channel 34 of the vacuum probe 32a. In a
closed state of the vacuum probe 32a, the valve element 38 bears
against a valve seat 50 inside the vacuum probe 32a. FIG. 2 depicts
a situation in which the valve element 38 is separated from the
valve seat 50, which separation allows air to flow from the vacuum
channel 34 out through opening 58 when vacuum pressure is applied
at opening 58.
[0031] As seen in FIG. 2, the valve element 38 comprises a forward
portion 40 which protrudes through opening 58. During quick
connection, the end face of the forward portion 40 of the valve
element 38 is acted upon by the valve core of the female quick
connect/disconnect coupling element 26 of the vacuum hose 28. More
specifically, the valve core (not shown in the drawings) forces the
valve element 38 to displace downward and away from the valve seat
50. The valve element 38 is displaceable along an axis of the
vacuum channel 34. This inward displacement causes the valve
element 38 to move away from the valve seat 50, thereby opening the
vacuum channel 34 inside the vacuum probe 32a. When the vacuum
probe 32a is open, the sealed space underneath the vacuum bag 18
can be evacuated by applying vacuum pressure from the vacuum source
30 via the vacuum hose 28 and the vacuum probe 32a.
[0032] Still referring to FIG. 2, the vacuum probe 32a comprises a
vacuum channel 34 having an axis and openings 58 and 59 at opposite
ends thereof. The vacuum probe 32a further comprises a sharpened
body 46 that points away from opening 58 of the vacuum channel 34
and projects outside of the vacuum channel 34 in a vicinity of
opening 59. As previously mentioned, the vacuum probe 32a
comprises: a valve seat 50 surrounding the opening 58 of the vacuum
channel 34; a valve element 38 that is axially displaceable in the
vacuum channel 34 between first and second axial positions, the
valve element 38 being in contact with the valve seat while in the
first axial (i.e., closed) position and being separated from the
valve seat 50 while in the second axial (i.e., open) position; and
a rod 42 disposed in the vacuum channel 34. The rod 42 has a first
end to which the sharpened body 46 is fixedly coupled by means of
an air-permeable sharpened body support element 44 and a second end
that is connected to the valve element 38. In this embodiment, the
sharpened body 46 is axially displaceable in tandem with the valve
element 38 as the valve element 38 moves toward the second axial
position. In addition, the sharpened body 46 projects outside the
vacuum channel 34 when the valve element 38 is in the second axial
position.
[0033] As seen in FIG. 2, when the vacuum probe 32a is added and
sealed to the exterior surface of a vacuum bag 18 using
donut-shaped sealing material 48a that is tacky on both sides, the
vacuum probe 32a itself becomes a sealed-off environment. Different
forms of sealing material can be utilized, such as sealing tape or
a sealing gasket, provided that the sealing element has sufficient
height to create a volume of space under the bottom of the vacuum
probe 32a that allows the sharpened body 46 to project downward for
puncturing the uplifted vacuum bag. The donut-shaped sealing
material 48a may comprise a conformable, tacky, putty-like material
for removably adhering the vacuum probe 32a to the exterior surface
of the vacuum bag 18. In this regard, the donut-shaped sealing
material 48a may comprise a partially cured rubber compound that is
inherently tacky and that may be used to form an airtight seal
between the vacuum probe 32a and the exterior surface of the vacuum
bag 18. The donut-shaped sealing material 48a may be provided in a
composition that is generally soft and pliable during
room-temperature installation of the vacuum bag assembly 10, and at
elevated temperatures associated with processing (e.g., curing or
solidifying) the composite part 4.
[0034] Prior to quick connection of the vacuum probe 32a and the
vacuum hose 28, the sharpened body 46 is recessed slightly (not
shown in the drawings) inside the vacuum channel 34 for safety
reasons, but is displaced downward and toward the vacuum bag 18
during vacuum hose quick connection. During quick connection, the
sharpened body 46 and the valve element 38 move in tandem in the
vacuum channel 34 until the sharpened body 46 projects through
opening 59 and outside the vacuum channel 34, as depicted in FIG.
2. A vacuum pressure applied via the vacuum hose 28 pulls the
vacuum bag 18 upwards and towards the sharpened body 46, which
punctures the vacuum bag 18, thereby enabling air under the vacuum
bag 18 to be evacuated via the vacuum probe 32a as vacuum pressure
continues to be applied.
[0035] FIG. 3 is a diagram representing an orthographic view of a
portion of a device which is incorporated in the vacuum probe 32a
depicted in FIG. 2 and which is designed to puncture a vacuum bag
18 in response to a quick connection of vacuum probe 32a and vacuum
hose 28. This device is an air-permeable sharpened body support
element 44 in the form of a disk having six through-holes 54 which
allow air to flow upward in the vacuum channel 34 during
evacuation. The first end of rod 42 and the sharpened body 46 are
affixed to the air-permeable sharpened body support element 44 to
form a rigid assembly that displaces (e.g., slides) inside the
vacuum channel 34 in tandem with the valve element 38 (not shown in
FIG. 3). In accordance with alternative embodiments, the
air-permeable sharpened body support element 44 may be in the form
of a plug of porous material configured to slide up and down inside
the vacuum channel 34.
[0036] FIG. 4 is a diagram representing a partially sectional view
of a vacuum probe 32b in accordance with another embodiment. As
seen in FIG. 4, when the vacuum probe 32b is added and sealed to
the exterior surface of a vacuum bag 18 using a stack of two layers
of donut-shaped sealing material 48a and 48b having adhesive on
both sides, the vacuum probe 32b itself becomes a sealed-off
environment. More than two layers of donut-shaped sealing material
can be stacked.
[0037] As was the case in vacuum probe 32a depicted in FIG. 2,
vacuum probe 32b has a valve seat 50 that surrounds an opening 58
and a valve element 38 that bears against the valve seat 50, which
elements interact in the manner previously described. FIG. 4
depicts a situation in which the valve element 38 is separated from
the valve seat 50, which separation allows air to flow from the
vacuum channel 34 out through opening 58 when vacuum pressure is
applied at opening 58. As seen in FIG. 4, the valve element 38
comprises a forward portion 40 which protrudes through opening 58.
During quick connection, the end face of the forward portion 40 of
the valve element 38 is acted upon by the valve core of the female
quick connect/disconnect coupling element 26 of the vacuum hose 28
in the manner previously described with reference to FIG. 2 to
cause the valve element 38 to move away from the valve seat 50,
thereby opening the vacuum channel 34.
[0038] Still referring to FIG. 4, the vacuum probe 32b comprises an
externally threaded portion 12 projecting downward from a bottom of
the vacuum probe 32b. The vacuum channel 34 extends from opening 58
at the top of vacuum probe 32b to opening 59 at the bottom of the
externally threaded portion 12. The externally threaded portion 12
projects into the space that is surrounded by the layers of
donut-shaped sealing material 48a and 48b. A sharpened body 46
projects out of the vacuum channel 34 and beyond opening 59 formed
in the bottom of the externally threaded portion 12. It should be
appreciated that although vacuum probe 32b includes an externally
threaded portion 12, the external threads are not used. This
capability enables some existing vacuum probes having an externally
threaded portion for threaded coupling with a base to be modified
or supplemented to provide the vacuum bag puncturing capability
disclosed herein without using a base (see, e.g., base 6 in FIG.
1).
[0039] In contrast to the vacuum probe 32a depicted in FIG. 2, the
vacuum probe 32b depicted in FIG. 4 does not have a rod 42. Instead
the vacuum probe 32b comprises an air-permeable sharpened body
support element 56 in the form of a plug of porous material, which
porous plug is inserted into the bottommost portion of the vacuum
channel 34. In an alternative embodiment, the air-permeable
sharpened body support element 56 which supports the sharpened body
46 may comprise a disk having a plurality of through-holes. Whether
in the form of a plug or a disk, the material of the air-permeable
sharpened body support element 56 should be sufficiently malleable
to allow the plug or disk to be easily but securely press fit or
wedged into the vacuum channel and easily removed. Preferably the
air-permeable sharpened body support element 56 comprises an
annular flange 58 that bears against a bottom surface of the
externally threaded portion 12, serving to block further insertion
of the plug or disk into the vacuum channel 34. In this embodiment,
the sharpened body 46 is not recessed into the vacuum channel and
instead projects downward toward the vacuum bag 18. When a vacuum
pressure is applied via the vacuum hose 28 and vacuum probe 32b
pulls the vacuum bag 18 upwards and towards the sharpened body 46,
which punctures the vacuum bag 18. This puncture enables air
underneath the vacuum bag 18 to be evacuated via the vacuum probe
32b as vacuum pressure continues to be applied.
[0040] FIG. 5 is a diagram representing a partially sectional view
of a vacuum probe 32c in accordance with a further embodiment. FIG.
5A is a diagram representing a magnified view of a portion of the
vacuum probe 32c depicted in FIG. 5. Except for the components
depicted in FIG. 5A, the only other structural difference between
vacuum probe 32b depicted in FIG. 4 and vacuum probe 32c depicted
in FIG. 5 is that the upper end of the rod 42 seen in FIG. 5 is in
abutment with, not connected to the valve element 38. This is a
consequence of the fact that the rod 42 is inserted into the vacuum
channel 34 from the bottom of a vacuum probe having an externally
threaded portion 12 (e.g., of the type depicted in FIG. 1).
However, as long as the end of the rod 42 is in contact with the
valve element 38, then the sharpened body 46 will move downward in
tandem with the valve element 38 during quick connection in the
manner previously described. As will be explained in more detail
with reference to FIG. 5A, a spring 74 urges the sharpened body 46
upward toward a recessed position (not shown in the drawings). When
the sharpened body 46 moves downward in tandem with the valve
element 38 during quick connection, the sharpened body 46 will
reach a position in which its tip projects outside of the vacuum
probe and is exposed to the uplifting outer vacuum bag 18.
[0041] FIG. 5A is a diagram representing a magnified view of a
portion of the vacuum probe 32c depicted in FIG. 5. The vacuum
probe 32c comprises an externally threaded portion 12 projecting
downward from a bottom of the vacuum probe. The vacuum probe 32c
further comprises an internally threaded end cap 64 that is
threadably coupled to the externally threaded portion 12 and a
chamber 68 which is affixed to the internally threaded end cap 64.
The internally threaded end cap 64 comprises an opening 66 through
which the sharpened body 46 passes when deployed, while the chamber
68 comprises an opening 72 through which the rod 42 passes.
[0042] The rod 42 has a bottom end affixed to an air-permeable
sharpened body support element 70 and a top end (not shown in FIG.
5A, but see FIG. 5) that abuts the valve element 38. The
air-permeable sharpened body support element 70 (which may, for
example, be similar to the air-permeable sharpened body support
element 44 depicted in FIG. 3) supports the sharpened body 46. In
this embodiment, the sharpened body 46 is axially displaceable in
tandem with the valve element 38 as the valve element 38 moves
toward its second axial position. The air-permeable sharpened body
support element 70 is configured to slide up and down inside the
chamber 68. A spring 74 is disposed between the air-permeable
sharpened body support element 70 and the internally threaded end
cap 64 for urging the air-permeable sharpened body support element
70 upward. In the uppermost position of the air-permeable sharpened
body support element 70 (not shown in FIG. 5A), the tip of the
sharpened body 46 will be recessed (i.e., will not project below
the bottom surface of the internally threaded end cap 64. In
contrast, when the valve element 38 is displaced downward and
reaches its second axial position, the tip of the sharpened body 46
will project below the bottom surface of the internally threaded
end cap 64.
[0043] To facilitate the flow of air through the vacuum channel 34
during evacuation, the internally threaded end cap 64 may comprise
through-holes 76 which allow air to flow into the chamber 68, while
the chamber 68 may comprise through-holes 78 which allow air to
flow out of the chamber 68 and into the vacuum channel 34. In
alternative embodiments, the sharpened body support element is not
air-permeable, in which case the through-holes 78 in the chamber 68
may be placed at a lower elevation, i.e., below the elevation of
the bottom surface of the sharpened body support element when the
latter is in its lowermost position.
[0044] The various embodiments disclosed in some detail above have
the potential to provide cost savings due to time saved from bag
reworking. Also the likelihood of optimal processing of composites
during curing can be ensured by enabling the easy placement of
additional vacuum probes when circumstances suggest that would be
helpful.
[0045] While systems and methods for applying vacuum pressure to
composite parts have been described with reference to various
embodiments, it will be understood by those skilled in the art that
various changes may be made and equivalents may be substituted for
elements thereof without departing from the scope of the teachings
herein. In addition, many modifications may be made to adapt the
teachings herein to a particular situation without departing from
the scope thereof. Therefore it is intended that the claims not be
limited to the particular embodiments disclosed herein.
[0046] The method claims set forth hereinafter should not be
construed to require that the steps recited therein be performed in
alphabetical order (any alphabetical ordering in the claims is used
solely for the purpose of referencing previously recited steps) or
in the order in which they are recited unless the claim language
explicitly specifies or states conditions indicating a particular
order in which some or all of those steps are performed. Nor should
the method claims be construed to exclude any portions of two or
more steps being performed concurrently or alternatingly unless the
claim language explicitly states a condition that precludes such an
interpretation.
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